Igniter wire insulator assembly

ABSTRACT

An assembly for use in insulating an electrical igniter wire from the heat and erosion effects of rocket motor exhaust gases. The wire is enclosed in an envelope consisting of a Teflon covering and a stainless steel shield. The enveloped wire is disposed in a slot of the igniter arm and protected by an insulator at its point of connection with the igniter pin.

United States Patent 1191 1111 3,840,693 Honeycutt Oct. 8, 1974 [54] IGNITER WIRE INSULATOR ASSEMBLY 3,435,726 4/1969 Gabler 89/l.8l4 x 3,504,593 4/1970 R'cks et 211...... 89/l.814 X [75] Invent: Hmeycu! Madlsm, 3,513,749 5/1970 M agnant 89/l.8l4 x [73] Assignee: The United States of A e i as 3,765,339 /1973 De Angelis et a1. 102/702 R X represented by the Secretary of the Army, Washington, DC. Primary ExaminerLaramie E. Askin Attorney, Agent, or Firm-,-Edward J. Kelly; Herbert [22] Ffled' 1974 Berl; Charles R. Carter [21] Appl. No.: 431,821

[57] ABSTRACT [52] US. Cl. 174/70 R, 89/l.814 [51] Int. Cl F4lf 3/04 An assembly for use m msqlatmg elecmcal gmter [58] Field of Search 174/68 R R 74 wire from the heat and eroslon effects of rocket motor 317/79 8089/1814 28 A 102/502 exhaust gases. The wire is enclosed in an envelope 702 consisting of a Teflon covering and a stainless steel shield. The enveloped wire is disposed in a slot of the [56] References Cited igniter arm and protected by an insulator at its point UNITED STATES PATENTS of connection with the igniter pin. 2,479,590 8/1949 Pollock 89/135 UX 2 Claims, 1 Drawing Figure 18(STAIN LESS STEEL) 26 (PHENOLIC ASBESTOS) PATENTEDncr 8 I374 ("TEE-"LON" I6 |8(STA|NLESS STEEL) 26 (PHENOLIC ASBESTOS) 1 IGNITER WIRE INSULATOR ASSEMBLY BACKGROUND OF THE INVENTION This invention relates to the field of igniter wire insulator assembliesfCurrent concepts for insulating the igniter wire from rocket exhaust have resulted in numerous failures during field use. After a number of rocket firings, the insulation has eroded away and caused electrical shorts in the electrical system of the rocket launcher.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING The single FIGURE shown is a sectional view of the igniter wire insulator assembly carried by an igniter arm.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference numeral indicates an igniter arm having a slot 12 therein for carrying an electrical igniter wire 14. This igniter wire is enclosed in an envelope which includes a Teflon insulation covering 16 and a stainless steel shielding tube 18. The igniter wire is connected to an igniter pin 20 between washers 22 and secured thereto by a lock nut 24. An insulator 26 of phenolic asbestos material is provided with a wire passageway 28 therein for protecting the wire and shielding tube from the point where it leaves the igniter arm to where it is connected to the igniter pin. The slot 12 in the igniter arm further envelops the wire for protection against the rocket motor exhaust gases. The use of a stainless steel shielding tube and a phenolic asbestos insulator has provided a successful solution to the heat and erosion effects of rocket exhaust gases on igniter wires.

I claim:

1. An assembly for enveloping and insulating an igniter wire from rocket motor exhaust gases comprising: an igniter arm provided with a slot therein; an igniter wire disposed in said slot, said wire being provided with an insulation covering; a stainless steel shielding tube encompassing said insulated wire and an insulator enclosing said wire and said tube for protection against erosion of said exhaust gases.

2. An assembly as set forth in claim 1 wherein said insulation covering is polytetrafluoroethylene and said insulator is phenolic asbestos. 

1. An assembly for enveloping and insulating an igniter wire from rocket motor exhaust gases comprising: an igniter arm provided with a slot therein; an igniter wire disposed in said slot, said wire being provided with an insulation covering; a stainless steel shielding tube encompassing said insulated wire and an insulator enclosing said wire and said tube for protection against erosion of said exhaust gases.
 2. An assembly as set forth in claim 1 wherein said insulation covering is polytetrafluoroethylene and said insulator is phenolic asbestos. 